Leveraging Evolutionary Tuning for Enhanced Building Model Parameter Optimization
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This study discusses an evolutionary approach to optimizing building model parameters, resulting in significant reductions in monthly electrical usage by nearly 20% (250 kWh) and hourly consumption by over 10% (700 kWh). The methodology employs various evolutionary computation techniques including genetic algorithms and particle swarm optimization. It simulates natural selection to fine-tune 108 real-valued parameters, enhancing model accuracy by minimizing errors between simulated outputs and actual sensor data. Future work aims to integrate machine learning and refine fitness functions for further optimization.
Leveraging Evolutionary Tuning for Enhanced Building Model Parameter Optimization
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Presentation Transcript
Evolutionary Tuning of Building Model Parameters Aaron Garrett Jacksonville State University
Conclusion Evolutionary approach reduces electrical… • monthly SAE by almost 20% (250 kWh) • hourly SAE by over 10% (700 kWh) • hourly RMSE by over 7%
Evolution is a search algorithm • Type of beam search • Less vulnerable to local optima • Optimizes based on environment
Evolutionary computation • Simulates evolution by natural selection • Genetic algorithms • Evolution strategies • Genetic programs • Particle swarm optimization • Ant colony optimization • Problem domain information is invaluable
An evolutionary approach • Individual: Building parameters • Fitness: Error between E+ output and sensor data
What is an individual? • Defined by 108 real-valued parameters • Material • Thickness • Conductivity • Density • Specific Heat • Thermal Absorptance • Solar Absorptance • Visible Absorptance • WindowMaterial:SimpleGlazingSystem • U-Factor • Solar Heat • ZoneInfiltration:FlowCoefficient • Shadow Calculation Frequency
What is the fitness? Individual Model Error Fitness Actual Building Data
How do they evolve? Mom Sister Dad Brother
How are offspring produced? • Average each component • Add Gaussian noise
EC parameters • Population size 16 • Tournament selection (tournament size 4) • Generational replacement with weak elitism (1 elite) • Gaussian mutation (mutation rate 10% of variable range) • Heuristic crossover
Building model search space • 108 dimensions • Effectively infinite because continuous-valued • Limit here is 1024 simulations per search • Approximately what could be done in a weekend on single-core processor • 1024 is incredibly small number of samples
How do we get more for less? • EnergyPlus is slow • Full-year schedule • 8 – 10 minutes per simulation • Use abbreviated 4-day schedule instead • Jan 1, Apr 1, Aug 1, Nov 1 • 15 – 30 seconds per simulation
Will that even work? • 4 independent random trials • 1024 simulations per trial • Samples taken from high to low error r = 0.96 r = 0.94 Monthly Electrical Usage Hourly Electrical Usage
The less expensive approach Individual Model Error Fitness Actual Building Data
About that actual data… • 2% of the 15-minute measurements failed • Monthly electrical usage • Just ignore missing data (treat as 0) • Hourly electrical usage • Any hour containing a single failure was counted as a failure (8%) • Failures were not counted in error measure
Evolve using 4-day schedule • 8 independent trials • 1024 simulations per trial 15% 13% 9% 8% 6% 7% 26% 35% 60% Monthly SAE Hourly SAE Hourly RMSE
And the full year schedule? • Only run on hourly usage • 8 independent trials • 1024 simulations per trial 9% 11% 8% 12% 6% 7% 7% 10% Hourly SAE Hourly RMSE
Combining the two… Evolve Evolve
Serial evolution • 8 independent trials • 1024 simulations per trial • 768 simulations for abbreviated; 256 simulations for full 11% 11% 12% 9% 7% 7% 10% 8% Hourly SAE Hourly RMSE
Combining a different way… On-deck Circle
Parallel evolution • 8 independent trials • 256 simulations for full year schedule • 768 simulations for abbreviated schedule 11% 10% 9% 10% 7% 7% 8% 9% Hourly SAE Hourly RMSE
Conclusion Evolutionary approach reduces electrical… • monthly SAE by almost 20% (250 kWh) • hourly SAE by over 10% (700 kWh) • hourly RMSE by over 7%
What’s next? • Incorporate machine learning as fast island • Include temperature errors in fitness • How should this be combined with electrical usage error? • Should the be optimized separately with EMO approach?